Poult Enteritis Mortality Syndrome, or PEMS, weakens the turkey's immune
system, leaving it highly vulnerable to bacterial and parasitic infections. But
the new discovery could lead to better understanding and--eventually--treatment
and prevention.

PEMS outbreaks in the Southeast have cost the turkey industry millions of
dollars in losses annually. Other outbreaks have been reported in Texas and
Virginia. PEMS-related mortality ranges between 25 to 96 percent in affected
flocks. Birds that recover reach only about 40 percent of typical market
weight.

The syndrome is apparently a deadly combination of viruses. Specific
causative agents have not yet been identified, according to microbiologist
Stacey L. Schultz-Cherry at the ARS
Southeast
Poultry Research Laboratory in Athens, Ga. But she and ARS colleagues,
collaborating with NCSU veterinarian John Barnes in Raleigh, N.C., found that
PEMS strikes first in the thymus, or lymphoid glands of turkeys. Very few
viruses are known to grow in the thymus. The ability of a virus to infect the
thymus is a special concern because it is a designated disease fighter.

The researchers recently isolated one virus from the thymus of a turkey sick
with PEMS. They are attempting to identify it and determine its role in PEMS.
The research will aid in developing diagnostic tools and treatments to prevent
future outbreaks.

Increased vigilance on turkey farms has decreased the incidence of PEMS, But
before scientists can develop effective treatments, they need to learn much
more about the causative agent or agents and their effects on the turkey's
immune response.